Companies involved in Aldi’s national re-roofing rollout programme include:
• Architect: The Harris Partnership
• Project Management: Edge – Property and construction consultancy
• Main Contractors: Jupiter Construction Zenith Construction
• Sub-Contractors: Martin Brooks – roofing contractor Complete Roofing Systems – roofing contractor
Nationwide Specialist Services – services provider Jennings Roofing – roofing contractor
Lovetts Roofing – roofing contractor
Fosters Roofing – roofing contractor
• Builders’ Merchant: Burton Roofing Merchants
• Product Manufacturers: Onduline Building Products – ISOLINE LOW LINE Northstone Materials – roof tile manufacturer
When Aldi decided to centralise its approach to roof refurbishments, it marked a significant change in the way the supermarket chain manages its growing property estate.
Previously, re-roofing had been handled on a store-by-store basis, resulting in mixed materials, varying specifications and inconsistent performance across the UK. So Aldi sought a standardised specification that would deliver consistent quality, reliability and visual appeal across its national portfolio. To make this happen, Aldi turned to its appointed design team, including The Harris Partnership as architects and Edge as quantity surveyors, both of whom have extensive experience supporting the brand’s refurbishment and newbuild programmes.
A collaborative design meeting was held to explore the most effective approach to roof replacement across the estate, with input from key stakeholders helping to shape a robust and repeatable specification for future refurbishments.
“Aldi needed a solution that would provide consistent performance and appearance across all sites, but also one that could adapt to the practical realities of refurbishing existing buildings,” explains Aiden Salmons, Senior Costs Manager at Edge. “That meant accommodating a variety of roof types and conditions, from long rafter spans and ageing materials to ensuring the stores could stay open while the work was carried out. The specification had to be flexible, reliable, and robust enough to meet all of those demands.”
During initial discussions between specifiers, architects and contractors, builders’ merchant Burton Roofing introduced Onduline’s ISOLINE LOW LINE as a potential solution. While already recognised for its ability to support waterproofing at pitches as low as 10°, ISOLINE LOW LINE offered much more than just a pitch-based advantage. As a sub-roof system, it provided a secondary waterproofing layer that could accommodate a range of technical challenges, making it particularly suitable for re-roofing schemes where existing tiles needed to be reused or where long rafter lengths created vulnerability to water ingress.
With these benefits in mind, ISOLINE LOW LINE was integrated into the proposed specification and trialled at three Aldi stores: Gainsborough; Barnsley; and Shirebrook. These pilot sites allowed the project team to assess the system’s performance in real-world conditions. Following overwhelmingly positive results, Aldi approved the ISOLINE-based specification for full-scale national rollout.
Since these first trials, 16 more re-roofing projects have been completed for Aldi using the specification, with further schemes in the pipeline. Feedback from site teams and delivery partners has been consistently positive.
“One of the major advantages of ISOLINE is its ability to keep the roof watertight independently of the tiles,” adds Aiden. “This means stores can stay open throughout the works while keeping noise, dust and other disturbances to a minimum, which is critical for retail clients. It also creates a safer environment for contractors and customers alike, as the risk of falling debris is reduced while work is in progress.”
A key element of the programme’s success has been the collaboration between Onduline and Northstone Tiles. Previously, Northstone’s tiles weren’t suitable for use on Aldi’s roofs due to pitch and waterproofing constraints. However, by integrating ISOLINE LOW LINE into the specification, Aldi was able to retain the aesthetic and performance benefits of Northstone’s UK-manufactured tiles, even on stores with challenging roof designs. This has helped ensure consistency across the retailer’s estate while maintaining installation efficiency for delivery teams.
“Working with Onduline has enabled us to meet Aldi’s brief with confidence,” says Ken Anderson, National Sales Manager at Northstone Tiles. “Thanks to the ISOLINE LOW LINE system acting as the primary waterproofing layer, we’ve been able to supply our tiles to multiple Aldi stores, overcoming pitch and waterproofing issues that would otherwise have made this impossible. It’s helped deliver a durable, watertight, and visually consistent result that supports the goals of the wider re-roofing programme.”
Alongside its technical performance, ISOLINE LOW LINE has also been praised for its ease of installation, with contractors noting how the lightweight panels and familiar fixing method help speed up project delivery.
Onduline’s technical team has remained actively involved throughout, providing site support, training and guidance to ensure the system is applied correctly and consistently.
For Paul Duffy, Managing Director at Onduline Building Products, the Aldi programme is a strong example of how sub-roof solutions are evolving to meet complex refurbishment needs.
“This programme is a great example of what can be achieved through early collaboration and shared ambition,” says Paul. “By working closely with Edge, Northstone Tiles, and the wider Aldi team, we’ve supported the development of a robust and adaptable roofing specification. The ISOLINE LOW LINE system helps tackle modern-day challenges we’re seeing more often in refurbishment projects, whether it’s complex roof structures, tile reuse, or keeping buildings operational during works. It’s a privilege to see our system specified as part of such a prestigious and forward-thinking rollout.”
As Aldi continues to invest in the quality and consistency of its store environments, the ISOLINE LOW LINE system remains central to a specification that balances performance, safety and business continuity, all while extending the lifecycle of one of the most critical elements of the building envelope.
www.onduline.co.uk/ISOLINE